# 14.21. Can I write commerical software for KDE?

You can use the KDE libs to write "commercial and closed source" as well as "commercial and open source" software. If you write open source software you can use the Qt free edition. But if you write closed source software you may not use the Qt free edition; you'd have to obtain the Qt professional edition from Troll Tech.

If you want more information, please contact Troll Tech directly.